This invention relates to a pager receiver for receiving pager signals and a control station for transmitting the pager signals. Such a pager receiver and a control station are particularly useful in a radio communication network.
A pager receiver of the type described intermittently receives the pager signals. Each of the pager signals comprises a preamble signal having a preamble duration, a synchronization signal succeeding the preamble signal and having a synchronization duration, and an address signal succeeding the synchronization signal and having an address duration which is variable from the address signal to another address signal. The address signal may comprise a call number signal representative of a call number and a message signal representative of a message.
A control station is connected between a telephone network and a base station which has a service area in which the pager receiver can receive the pager signals. The control station comprises a processing circuit supplied with call information from the telephone network for processing the call information into processed signals to make the base station transmit the processed signals as the pager signals.
A recent remarkable development of an integrated circuit technique has rendered the pager receiver compact or portable and multifunctional. Preferably, the pager receiver has a long life. Inasmuch as a battery is used as a power source in the pager receiver, the pager receiver has a life time dependent upon the life of the battery. Therefore, electric power must not be wasted in the pager receiver. In other words, useless operation should strictly be restricted. For this purpose, a battery saving operation is carried out in such a pager receiver during nonreception of the pager signals.
In order to carry out the battery saving operation, the pager receiver comprises a battery saving switch having an on state and an off state. The pager receiver further comprises a switch operating circuit for putting the switch selectively in the on and the off states and a receiving circuit connected to the battery saving switch and enabled while the battery saving switch is put in the on state.
According to a conventional battery saving operation, the switch operating circuit puts the battery saving switch in the on state repeatedly at a predetermined time period shorter than the preamble duration to make the receiving circuit receive at least a portion of the preamble signal. Such an operation is called a sampling operation in the art. When the preamble signal is detected, the switch operating circuit keeps the battery saving switch in the on state until an end of the address signal to make the receiving circuit receive whole of the synchronization and the address signals. From the end of the address signal, the switch operating circuit puts the battery saving switch in the off state and then puts the battery saving switch in the on state repeatedly at the predetermined time period. It is to be noted here that the sampling operation is repeated between the pager signals at the predetermined period shorter than the preamble duration.
The conventional battery saving operation has, therefore, an insufficient battery saving efficiency because the sampling operation is repeated between the pager signals. In particular, the sampling operation may be useless at night because a small number of calls is given to the pager receiver at the night.